1. Field of the Invention
The present invention relates to a display panel displaying stereo images, and in particular relates to a display panel reducing areas of shade regions and raising brightness by changing the arrangement of images displayed on the display panel, and a display device using the same.
2. Description of the Related Art
Currently, stereo image displays are popular. In order to provide high quality to users, manufacturers have made efforts to develop and improve stereo image display technology. Glasses stereo image display technology is used as a main type of stereo image display technology. The glasses stereo image display technology comprises polarized glasses technology and shutter glasses technology. Generally, the concept of displaying a stereo image is that a left eye image and a right eye image, constituting a stereo image, are transmitted to the left eye and the right eye, of a viewer, respectively, such that a three-dimensional image can be constructed in the viewer's brain.
FIG. 1A is a front view showing a basic structure of a conventional display panel. FIG. 1B is a lateral view showing the conventional display panel of FIG. 1A, which is used to a polarized glasses type stereo image display panel.
As shown in FIG. 1A, a display panel 1 comprises: a plurality of pixels P11˜Pnm, arranged in a matrix formed by rows and columns, wherein m and n are integers greater than 1; a source driver 2, outputting data signals to all pixels P11˜Pnm via source lines 6-1˜6-m; and a gate driver 3, outputting scan signals via gate lines 7-1˜7-n to control the periods when the data signals are input to the pixels P11˜Pnm. As shown in FIG. 1B, a display panel 1, from the back side to the front side, comprises a lower substrate 11a, a liquid crystal layer 11, an upper substrate 11b, a polarizer 12, a quarter wave plate 13, a retardation film 14, and black strip patterns 15. The lower substrate 11a comprises an inner surface 11a1 and an outer surface 11a2. The upper substrate 11b comprises an inner surface 11b1 and an outer surface 11b2. The liquid crystal layer 11 is sandwiched between the inner surface 11a1 of the lower substrate 11a and the inner surface 11b1 of the upper substrate 11b. On the inner surface 11b1 of the upper substrate 11b, there are a number of black matrixes BM disposed between adjacent rows of pixels. Note that for other display technologies, the black matrixes BM are able to be disposed on the inner surface 11a1 of the lower substrate 11a. 
To make each eye of the viewer receive an exclusive image, the source driver 2 of the display panel 1 inputs left eye image data to odd row pixels and right eye image data to even row pixels, so that the odd row pixels can be used to display left images and the even row pixels can be used to display right images, as shown in FIG. 1B. After the light passes through the polarizer 12, there is a linear polarized light with a fixed polarization direction. The linear polarized light is converted to a circular polarized light (for example, a left circular polarized light in FIG. 1B) by the phase retardation effect of the quarter wave plate 13. The retardation film 14 comprises a plurality of portions arranged in rows, wherein the phase retardation of each odd row portions is 0λ and the phase retardation of each even row portions is ½λ. When the display panel 1 is fabricated, the odd row portions of the retardation film 14 are aligned with the liquid crystal layer 11 belonging to the odd row pixels, and the even row portions of the retardation film 14 are aligned with the liquid crystal layer 11 belonging to the even row pixels. Therefore, in the case where the left circular polarized light passes through the odd row portions of the retardation film 14, the left circular polarized light will be the same with no phase retardation. In the case where the left circular polarized light passes through the even row portions of the retardation film 14, the left circular polarized light will be converted to a right circular polarized light for ½λ phase retardation.
A pair of polarized glasses 16 shown in FIG. 1B is used to make the left eye and the right eye of the viewer to receive exclusive images, respectively. A left glass 17 of the polarized glasses 16 is a left circular polarizer allowing the left circular polarized light to pass and making the right circular polarized light to be absorbed. A right glass 18 of the polarized glasses 16 is a right circular polarizer allowing the right circular polarized light to pass and making the left circular polarized light to be absorbed. Accordingly, the left eye image displayed by the odd row pixels can pass through only the left glass 17 and will be received by the viewer's left eye, and the right eye image displayed by the even row pixels can pass through only the right glass 17 and will be received by the viewer's right eye.
The black strip patterns 15 shown in FIG. 1B are disposed on the boundary regions between the odd row portions and the even row portions of the retardation film 14. The purpose of the black strip patterns 15 is to increase the vertical view angle for the viewer to see the stereo images correctly. Namely, within a predetermined view angle range, the black strip patterns 15 can block error images from being transmitted to the viewer. For example, when a viewer faces to the display panel 1 and moves upward and downward, the black strip patterns 15 block polarized light from passing through the boundaries between the odd row portions and the even row portions of the retardation film 14, to prevent the left eye of the viewer from receiving the right eye image or the right eye of the viewer from receiving the left eye image. That is to say, viewers are kept away from receiving the light passing through the liquid crystal layer 11 belonging to the odd row pixels and the even row portions of the retardation film 14, or the light passing through the liquid crystal layer 11 belonging to the even row pixels and the odd row portions of the retardation film 14, such that the view angle can increase.
Note that in the above structure of the polarized glasses type stereo image display panel, the quarter wave plate 13 can be removed. In this case, the phase retardation of the odd row portions of the retardation film 14 will be ¼λ, and the phase retardation of the even row portions of the retardation film 14 will be −¼λ. Therefore, the effect of this structure is the same as that of the structure described previously. Note that the black strip patterns 15 can be disposed on any particular surface of the retardation film 14.
FIG. 2 is a diagram showing a conventional stereo image display method. In FIG. 2, the left eye image data Lsource, from top to bottom, is divided into a plurality of left eye image row data L1, L2, L3 . . . ; and the right eye image data Rsource, from top to bottom, is divided into a plurality of right eye image row data R1, R2, R3, . . . . When the left eye image data Lsource and the right eye image data Rsource are input to the conventional display panel, the left eye image row data and the right eye image row data, from top to bottom, are arranged in the order L1, R1, L2, R2, L3, R3, L4, R4, . . . , as described previously. The black strip patterns 15 are disposed between the odd row pixels displaying the left eye image constituted by the left eye image row data L1, L2, L3, L4, . . . , and the even row pixels displaying the right eye image constituted by the right eye image row data R1, R2, R3, R4, . . . . In FIG. 2, the symbol “w” represents the width of a black strip pattern. Generally, the width of the black strip pattern is made greater than the width of the black matrix BM so as to obtain a wider vertical view angle.
FIG. 3 is a vertical view angle-crosstalk curve diagram in the case where different widths of the black strip patterns are provided. The horizon axis represents the vertical view angle relative to the display panel. The vertical axis represents the degree of the crosstalk. Curve a represents a state wherein no black strip patterns exist. Curve b represents a state wherein the width of each black strip pattern is 30 μm. Curve c represents a state wherein the width of each black strip pattern is 60 μm. Curve d represents a state wherein the width of each black strip pattern is 90 μm. From FIG. 3, it is understood that under the same degree of crosstalk (for example, 7%), the vertical view angle of the display panel with black strip patterns is greater than the vertical view angle of the display panel having no black strip pattern, and the vertical view angle increases as the width of the black strip patterns increases.
However, even though the arrangement of the black strip patterns reduces of signal interference and increases the vertical view angle, transparent areas of the display panel will decrease, causing brightness of the display panel to decrease. Assuming that the width of a black strip pattern is a % of the width of a pixel, the brightness of the entire display panel would decrease to 1−a % because the number of the black strip patterns is equal to the number of the rows of the pixels. Therefore, the purpose of the invention is to provide a stereo image display panel or a stereo image display device capable of improving the drawback of low brightness.